Summary The goal of the 2020 GRC and GRS on DNA Damage, Mutation and Cancer is to stimulate research through scientific dialog on the genomic changes and cellular responses that underlie cancer susceptibility. The GRS will be from February 29-March 1, 2020 and the GRC will follow on March 1-6, 2020, both at the Ventura Beach Marriott in Ventura, CA. The GRC takes place at a period when interest in DNA damage, its genomic impact, relationship to cancer, and exploiting DNA damage susceptibilities to develop new therapies is at an all-time high. Not only does this field provide critical insight to the consequences of DNA damage for genome integrity and cancer avoidance, but also genome editing requires understanding and manipulating DNA repair, and the opportunity to treat cancer with novel checkpoint inhibitors is bolstered by underlying defects in DNA repair and replication stress responses. DNA damage occurs during replication and also during other cell cycle phases though base modifications, adducts, DNA nicks and breaks, aberrant DNA structures, and other causes. The impact of DNA damage is far reaching, inducing an inflammatory response, a checkpoint response, and mutation. Understanding causes of mutation, consequences of mutation at the genome level and how this translates into cancer risk, and exploiting DNA damage responses are goals of these meetings. The GRS has invited talks and talks chosen from abstracts based on new findings and impact of the research. There will be a mentorship session, with presentations from early and midcareer scientists, scientists from industry and the publishing sector. The GRC has speakers from an international makeup, representing academia, industry and physician scientists. There will be a mix of senior, midcareer and early investigators. The GRS will have poster sessions each day to stimulate individual interactions and to meet trainees. Some poster presenters will be chosen for late-breaking short talks. The Power Hour afternoon session will discuss challenges to women in science, challenges to minorities in science, and establish new networking interactions. At some of the dinners there will be theme tables, one night based on scientific topics and another night based on mentoring and career options, to encourage participation of students and postdocs and to help interactions between these groups and senior scientists. Many of the speakers are new to this conference and the Gordon conferences. There are 3/6 females among the invited participants for the GRS and 12/33 females among the invited participants for the GRC. Nine speakers are at the early-mid stage career level and all speakers represent ten different countries. We continue to do outreach to underrepresented minorities.